Make UIColor Codable

Question

struct Task: Codable {     var content: String     var deadline: Date     var color: UIColor ... } 

There are warnings saying "Type 'Task' does not conform to protocol 'Decodable'" and "Type 'Task' does not conform to protocol 'Encodable'". I searched and found that this is because UIColor does not conform to Codable. But I have no idea how to fix that. So...

How to make UIColor Codable?

Answer 1

If you care only about the 4 color components this is a simple solution using a wrapper struct

struct Color : Codable {     var red : CGFloat = 0.0, green: CGFloat = 0.0, blue: CGFloat = 0.0, alpha: CGFloat = 0.0          var uiColor : UIColor {         return UIColor(red: red, green: green, blue: blue, alpha: alpha)     }          init(uiColor : UIColor) {         uiColor.getRed(&red, green: &green, blue: &blue, alpha: &alpha)     } } 

In this case you have to write a custom initializer to convert the 4 color components from Color to UIColor and vice versa.

struct Task: Codable {          private enum CodingKeys: String, CodingKey { case content, deadline, color }          var content: String     var deadline: Date     var color : UIColor          init(content: String, deadline: Date, color : UIColor) {         self.content = content         self.deadline = deadline         self.color = color     }         init(from decoder: Decoder) throws {         let container = try decoder.container(keyedBy: CodingKeys.self)         content = try container.decode(String.self, forKey: .content)         deadline = try container.decode(Date.self, forKey: .deadline)         color = try container.decode(Color.self, forKey: .color).uiColor     }          public func encode(to encoder: Encoder) throws {         var container = encoder.container(keyedBy: CodingKeys.self)         try container.encode(content, forKey: .content)         try container.encode(deadline, forKey: .deadline)         try container.encode(Color(uiColor: color), forKey: .color)     } } 

Now you can encode and decode UIColor

let task = Task(content: "Foo", deadline: Date(), color: .orange) do {     let data = try JSONEncoder().encode(task)     print(String(data: data, encoding: .utf8)!)     let newTask = try JSONDecoder().decode(Task.self, from: data)     print(newTask) } catch {  print(error) } 

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A smart alternative for Swift 5.1 and higher is a property wrapper

@propertyWrapper struct CodableColor {     var wrappedValue: UIColor }  extension CodableColor: Codable {     init(from decoder: Decoder) throws {         let container = try decoder.singleValueContainer()         let data = try container.decode(Data.self)         guard let color = try NSKeyedUnarchiver.unarchivedObject(ofClass: UIColor.self, from: data) else {             throw DecodingError.dataCorruptedError(                 in: container,                 debugDescription: "Invalid color"             )         }         wrappedValue = color     }      func encode(to encoder: Encoder) throws {         var container = encoder.singleValueContainer()         let data = try NSKeyedArchiver.archivedData(withRootObject: wrappedValue, requiringSecureCoding: true)         try container.encode(data)     } } 

and mark the property with @CodableColor

struct Task: Codable {     var content: String     var deadline: Date     @CodableColor var color: UIColor ... }